1. Field of the Invention
The present invention relates to an apparatus for detecting oil pressures and in particular to an oil pressure detecting apparatus which can be advantageously employed for an alarm system for indirectly monitoring an amount of oil in a Diesel engine.
2. Description of the Prior Art
In systems for detecting oil pressures particularly of internal combustion engines there has heretofore been known a so-called pressure switch having contacts which are adapted to be actuated mechanically by means of a bellows and a spring. It is also known to use a semiconductor strain gage for the same purpose. However, the pressure switch has a drawback that it can be used only for detecting a specific point of value of oil pressure. On the otherhand, the semiconductor strain gage is disadvantageously subjected to restriction in respect to the locations at which the gage is used due to the inherent temperature characteristic thereof. Further, the semiconductor strain gage is very expensive.